Is the Standard of Achieving a True Arthrodesis Being Overlooked?
Fixation of the SI joint can be an effective method for addressing mechanically-induced sacroiliac (SI) joint dysfunction. However, the question must be asked – is fixation of the joint enough? Or will fixation prove more effective with long-term fusion?
One of the fundamental principles of joint fusion is, “fusion through bleeding bone” and the SI joint is not an exception to this principle. By providing fixation, as well as facilitating fusion of the SI joint through decortication and bone grafting, true orthopedic principles are being employed to immobilize the joint.
Given the challenging location, biomechanical requirements, and intense loads borne by the SI joint, creation of a true SI joint arthrodesis can be difficult to achieve. In the past, open, more invasive surgeries would prepare the joint for fusion but led to numerous complications. Today, many technologies can reach the SI joint less invasively to achieve fixation, but lack the proper technology to create an environment for fusion.
The SI joint consists of intra-articular and extra-articular regions. The intra-articular region exhibits a much closer approximation of the joint surfaces and has a strong underlying cortical structure. As with all joints, the surface of the SI joint is lined with cartilage, an avascular tissue, which may inhibit a bony fusion. This cartilage could act as a biological barrier, explaining why autofusion does not typically occur, even with the small degree of normal motion in the SI joint. It may also limit the ability to fuse the joint via fixation alone. With proper site preparation, including cartilage removal and decortication, the articular region is a prime candidate for fusion.
The SImmetry System provides access to the joint by using tissue-sparing minimally invasive techniques:
- Joint Decortication: The proprietary SImmetry Decorticator allows you to prepare the articular region of the SI joint, creating a debrided area within the SI joint of 27mm.
- Bone Grafting: SImmetry facilitates collection and placement of autologous bone within the prepared joint.
- Fixation: A range of threaded implants is available to provide solid fixation during the fusion process.